Proportional representation

Pupils at Lampton comprehensive in Hounslow, west London, which takes racism and bullying seriously.

The racist graffiti proclaiming "Pakis Out" and "National Front" has long been airbrushed into history, but as I walk along the lane to my old school, Lampton comprehensive in Hounslow, west London, the memories come flooding back. The year is 1978 and I am a streetwise 12-year-old again, with a mop of bright red hair and dressed in a blazer two sizes too large that my mother insists I will grow into. In my satchel is my most precious possession: a record, Rat Trap, by the Boomtown Rats. By the end of my first week , the record has been shattered into a thousand pieces by a skinhead who hates "ginger nuts", along with any illusions I had that Lampton was going to be a happy experience.

Fast forward nearly 30 years and I am going back through the school gates to interview the current headteacher of Lampton, Susan John, to see how the school has changed. In the intervening period, Hounslow, in line with neighbouring Southall, has seen a large influx of Asian and black families and this is reflected in Lampton's intake of more than 75% ethnic minority pupils and fewer than 25% white, a reversal of the proportions in my day.

According to recent figures published by the government, ethnic minority pupils account for just less than a fifth of England's 6.5 million primary and secondary school pupils. Nick Johnson, director of policy at the Commission for Racial Equality (CRE), has warned that Britain risks becoming a mini-America, dominated by racially determined schools, and that increasing segregation is a "ticking time bomb".

In three decades, Lampton has doubled the number of pupils. According to a 2005 report by the education watchdog Ofsted, it still has a catchment that is "economically and socially disadvantaged". John joined the school in 1997, and in many ways Lampton can be seen as a barometer of Labour's record in state secondary education. The investment is impressive: a new speech and language centre and a big sports hall. In 2004, Lampton was designated a specialist humanities college and last year it produced its best-ever results, with 69% of pupils achieving five or more GCSEs at grades A* to C. In my time, too many pupils left with no qualifications at all.

And another big change from my years there: Lampton takes racism and bullying extremely seriously. "After 9/11 and 7/7 we had special assemblies to talk through all the issues," says John. "And we insist every half term that pupils change places in lessons so that they sit next to someone from a different race or religion. We also have a policy of tackling real and cyber bullying, whether it occurs inside or outside the school." I recall my second year at Lampton in which a bloody fight took place between an Asian teacher and a skinhead who was a National Front member.

By 1980, I had left Lampton. Money worries, and as fears that I would be influenced by the "wrong crowd" and struggle academically, prompted my parents to move out of London, and I completed my education in Norfolk.

The changing ethnic mix of Lampton's pupils illustrates how schools can be a contributing factor in areas becoming racially segregated. In 2005, a report from the pressure group MigrationWatch showed that in the previous decade more than 600,000 people, most white, had moved out of London while more than 720,000 immigrants had moved in.

Syed Mohsin Ali, who came to England from Pakistan in 1973 and has two sons at Lampton, shares concerns over a concentration of ethnic minorities in the catchment area. "There is far too great a concentration of ethnic minorities at the school," he says. "If you go there it's [a case of] 'spot the white'. My children don't know anything about the British way of life. They eat, drink and talk only with other Asians. They can't all get jobs at Heathrow or in Hounslow, and I'm worried they will feel alienated in the City and won't cut it. What the government needs to do is stop immigration."

But John defends Lampton, saying its intake mirrors the local community and that other local schools have more than 90% ethnic minority pupils.

It is also important to note that Lampton's impressive academic record is marred by the high exclusion rate of white pupils. The school's Ofsted report is extremely critical about what it describes as "white lower-attaining boys" and records that in 2005 almost 15% of white pupils were excluded (temporarily and permanently), a figure way above the national average and far higher than for any other group.

And Lampton is not alone. A Joseph Rowntree Foundation report published in February highlighted the problem of persistently poor educational standards among white working-class boys. It called for a reform of league tables, which it says discourages schools from admitting pupils who might lower their scores, and extra funding to better reflect disadvantage.

The CRE believes that the answer is for the government to introduce programmes targeted at underperforming groups, including white working-class pupils and other marginalised groups such as Gypsies and Travellers. Meanwhile, from September, every school will have a duty, enforced by Ofsted, to promote community cohesion. Twinning schools is one idea.

Lampton has a twinning project with a school in Uganda, but when I ask John if she has thought of twinning with a school slightly nearer home, perhaps one in Devon with a predominantly white intake, she shakes her head.

Johnson sums up the CRE's increasing concern: "Segregation and educational underachievement are a good recruiting sergeant for extremism," he says, "whether it is the British National party, Islamic extremism or the gang culture. These are the children who are ripe for exploitation".

· Email your comments to society@theguardian.com. If you are writing a comment for publication, please mark clearly "for publication"